1. Field of the Invention
The present invention relates to a device and a method to get a micro displacement of length.
2. Description of the Prior Art
A precision in the order of micron or nanometer is necessary when positioning is to be accomplished in such fields as precisely processing machine, precise handling of a device or precise operation of viewing range of a microscope. For the precise positioning of a part of an apparatus, there is required a device attached to or mounted on the part of the apparatus to establish a minute and accurate displacement of the part matching the required positioning precision. There has been sometimes used a piezoelectric element for this purpose. But as the output displacement get by the piezoelectric element is too small, it is generally necessary to convert to magnify the output for the above purpose. And because of necessity for an electric power, the piezoelectric element is troubled in portability.
For precise positioning, therefore, there has been widely used a fine adjusting mechanism to convert to reduce mechanically a large input displacement. In Japanese Patent Laid Open No. 145057/1977, for example, there is disclosed a finely displacing device in which, an input member is so mounted through a first set of rollers on a horizontal plane as to move horizontally. The input member has a slightly inclined upper surface, on which an output member is so mounted through a second set of rollers as to move vertically but not to move horizontally. If the upper surface of the input member has an angle of inclination of .alpha., the output member rises by a.multidot.tan (.alpha.) for a horizontal movement of .alpha. (mm) of the input member. Since the value .alpha. is small, the rise a.multidot.tan (.alpha.) of the output member is sufficiently small with respect to the horizontal displacement .alpha. of the input member. Thus, the fine displacement of the length is established.
However, the finely displacing device described above is required to manufacture the first and second sets of rollers precisely into cylindrical shapes and to precisely flatly work the faces of the input and output members contacting with the two sets of rollers. There is another problem that this device has its mounting posture to the part of the apparatus limited, that is, we can get only the vertical displacement by this device.